1. Technical Field
The invention relates to a frame for a bicycle trailer with a foldable passenger compartment and a foldable seat arranged therein.
2. Description of the Related Art
Bicycle trailers with a passenger compartment are gaining increased popularity as an alternative to bicycle child carriers that are mounted to the rear rack or the upper tube of the bicycle frame, because they provide far better protection for children.
The bicycle trailers must satisfy a variety of requirements. On one hand, they must have a sturdy and rigid passenger compartment so that the transported child is sufficiently protected in the event of an accident. It also must be ensured that the child cannot be readily thrown from the seat in the event of an accident. Moreover, the bicycle trailer frame should be lightweight in order to make pulling it as easy as possible. Finally, it should allow for space-saving storage.
The frame of such a bicycle trailer is generally comprised of four basic components, namely a rigid chassis forming the lower frame of a passenger compartment and bearing the axle and/or wheels and the drawbar; a foldable frame superstructure which forms the front, top and back of the passenger compartment; a seat that is braced between the apex of the foldable superstructure frame and the lower frame, and a covering made of fabric or plastic panels, which forms the outer casing of the trailer.
This covering essentially serves as weather protection and prevents children sitting in the trailer from getting their hands caught in rotating parts, such as for example the running wheels, or from touching the pavement with their feet while the trailer is in motion. There is an opening in the front through which the trailer can be boarded and which can be closed against wind, sun and rain by means of a separate cover that comes with the trailer. There is another closable opening at the back of the trailer which provides access to the storage space between the seat cloth and the rear wall of the trailer for loading and unloading purposes and which can be closed as well.
Often, the seat is formed by fabric panels stretched across the inside of the passenger compartment, which are usually separate from the external covering in order to allow for the bicycle trailer to be folded. In most cases, the seating area is fastened to the lower frame parallel thereto at its four corners either directly or with straps. The backrest, the lower edge of which is sewn firmly to the seating area, is braced in vertically at least at the two upper ends at the apex of the superstructure frame, often at a top crossbar. The shoulder straps of a restraint system, which is to prevent the child (children) from falling out of the trailer in the event of a collision or tipping of same, are attached to the backrest.
A major disadvantage of this embodiment is that the side edges of the backrest cannot be anchored to the frame because the passenger compartment could then no longer be folded. Due to the absence of such anchorage there is a risk that the restraining system, which is attached to the backrest, could, in the event of a collision or tipping, move together with the backrest and the child along with the rear wall either too far to the front or too far sideways, which would result in the loss of an essential part of the effectiveness of the restraint system. This effect is compounded by the fact that in order to achieve more shoulder width in the above described vehicles, the covering in the shoulder area is extended further sideways towards the outside with the help of an additional sub-frame, while the vertical edges of the backrest of the cloth seat remain straight. This creates a gap in the shoulder area between the edges of the backrest and the outer covering, through which, for example, objects stored in the storage compartment could slide into the passenger compartment in the event of an accident and lead to the passengers getting injured.